Self-locking clamping device



June 12, 1956 2,749,787

P. OLLAGNON SELF-LOCKING CLAMPING DEVICE Filed June 2, 1952 t ou-QM -lh i 2,749,787 lc Patented June 12, 1956 SELF-LOCKING CLAMPING DEVICE Paul ()llagnon, Saint-Etienne, France, assignor to Societe Anonyme ties Forges Stephanoises, Saint-Etienne (Loire), France Application June 2, 1952, Serial No. 291,116

Claims priority, application France June 6, 19 51 4 Claims. (CL lib-84) My invention has for its object a tool adapted to serve as a clamp or as a hand-operated vise, including an auxiliary lever controlling its operation and ensuring its self-locking, the preliminary adjustment of the relative angular setting of the jaws being obtained in both cases by means of a milled knob.

This clamping vise is characterized by the fact that it includes two levers of the third class having equal lengths and the cooperating ends of which engage each other, said levers carrying at their free ends jaws facing each other while the two levers are urged together with a view to producing a clamping of the jaws over the desired work by means of a transverse control system actuated through the agency of the auxiliary handoperated lever.

According to other optional features of my invention:

The preliminary adjustment of the control system is ensured by a nut engaging a threaded rod carrying a milled knob;

The tensioning is obtained by a relative transverse shifting of three parallel spindles of which two have axes fixed with respect to the levers carrying the jaws while the axis of the third spindle is fixed with respect to the auxiliary lever;

The relative adjustment of these three spindles brings their axes at the end of the operation of the auxiliary lever into a common plane which corresponds to a stable position of equillibrium.

I have illustrated in accompanying drawings a preferred embodiment of my invention. In said drawings:

Fig. l is an elevation and Fig 2 a side view of my improved tool.

Fig. 3 is a sectional view through line 3-3 of Fig. l.

Said tool includes two levers 1 and 2 of the third class, the lengths of which are equal and the three operative points of which are shown at ADC and BEG, respectively, the two levers engaging each other at their lower common end C through the agency of a pivot c while their upper free ends carry jaws A, B facing each other and adapted to held between them the work or part to be clamped.

The point D of the first lever 1 located between the jaw at A and the pivot or spindle corresponds to the location of a transverse pivot or spindle d and similarly the point E corresponding thereto on the second lever 2 corresponds to the location of a transverse pivot 2.

Between the spindles d and e is inserted an adjustable tensioning or control system providing for the movement towards each other of the points D and E and consequently for a clamping of the work between the two jaws A and B.

This system that is housed inside suitable recesses F, G of the levers 1 and 2, as shown in Fig. 2, is constituted as follows: to the spindle d on the first lever 1 is pivotally secured a small auxiliary lever 3 the three operative points of which are shown at D, H, I; said lever 3 carries at H a spindle h to which is pivotally secured the bent-strapshaped extension of a nut J. The latter, as illustrated in Fig; l is designed in a manner such that the spindle it carried by the bent strap crosses the axis of a threaded bore j of the nut I, while there is provided between the threaded part of the nut and the end of the strap-shaped extension a recess m extending across the axis of the threaded bore j and that is adapted to house the spindle d on the lever 3 when the hand-operated free end I of said auxiliary lever 3 is depressed so that said hand-operated end 1 comes nearer the lever 1.

Inside the nut J is screwed a threaded rod K which is actuated by a milled knob L that carries along with it the spindle 2 provided with a transverse bore fitted over the threaded rod K, said spindle being held in the embodiment illustrated between the knob L and the cooperating surface of the lever 2.

When the handle I of the auxiliary lever 3 is rocked downwardly while the spindle d is supposed to be stationary, the spindle h on said auxiliary lever 3 carries along with it the nut J and consequently also the spindle e through the agency of the threaded rod engaging the latter. The spindle e on the lever 2 is thus moved towards the spindle d on the lever 1 and consequently the two jaws A, B move nearer each other. Thus the depression of the auxiliary lever I provides the desired clamping operation.

When the threaded rod K is screwed into or out of the nut J as provided by actuation of the milled knob L, the final spacing obtained between the spindles d and e con sequently between the jaws A and B is modified. The milled knob L should be actuated in a manner such that the locking of a given. work to be clamped is accurately obtained at the end of the downward stroke of lever I, i. e. when the three transverse spindle axes h, d, e lie i n a common plane and consequently in a stable position whereby an instantaneous self-locking of the vise or clamp is obtained.

In order to further the operation of my improved tool, a spring R urges the two levers away from each other so that the tool may open automatically as soon as the lever I is raised again.

What I claim is:

1. A clamp of the class described, comprising in combination: first and second lever members; a main pivot means interconnecting said lever members for relative angular movement about a main axis; a pair of cooperating work-gripping means equally spaced from said main axis and each carried by one of said lever members, said gripping means comprising gripping surfaces effective to grip a workpiece therebetween throughout an appreciably large range of relative angular positions of said lever members; an operating lever; a first pivot means carried by said first lever member intermediate said main pivot means and one of said gripping means and connecting said operating lever to said first lever member for movement about a first axis parallel to and spaced from said main axis; a link member; a second pivot means connecting one end of said link members to said second lever member for movement about a second axis parallel to said main axis and spaced from said main axis by substantially the same distance as said first axis, said link member having an off-center recess formed in that side thereof confronting said main axis and said first pivot means, said first pivot means being nestable in said recess to permit another end of said link member to extend around and beyond said first pivot means; a third pivot means interconnecting said operating lever and said link member at said another end of said link member and at a portion of said operating lever spaced from said first pivot means, said third pivot means permitting relative movement between said link member and said operating lever about a third axis parallel to said main axis, said operating lever being movable to a locked position wherein said first, second and third axes are substantially coplanar and wherein said gripping surfaces are positively forced by movement of said operating lever to have a minimum spacing from each other, said operating lever being further movable to an open position wherein said third axis becomes spaced from one side of a plane containing said first and second axes and wherein said main axis is spaced from an opposite side of said last mentioned plane, whereupon said gripping surfaces become spaced from each other by a spacing greater than said minimum spacing; and adjusting means included in said link memher for varying the distance between said second and third axes for adjusting the magnitude of said minimum spacing betweensaid gripping surfaces in accordance with the size of a workpiece to be gripped in said clamp.

2. A clamp according to claim 1 wherein said adjusting means includes disengageable means which permits said gripping surfaces to be moved toward each other independently of said operating lever, and in which said clamp further comprises spring means yieldingly urging said gripping surfaces apart.

3. A clamp according to claim 1, wherein said operating lever comprises a handle portion, said handle portion, with said operating lever in said locked position, extending toward said main pivot means and in proximity to said first lever member.

4. A hand-operated clamp comprising two similarly shaped rectilinear levers pivotally secured to each other on a first axis adjacent their corresponding ends, cooperating jaws facing each other at the free ends of said levers, a pivot carried by one of said levers on a second axis intermediate the length of said one lever and spaced from said first axis, the other lever being provided with an arcuate recess in that side surface which faces away from the first lever and which is located at a distance from said first axis corresponding to the spacing of said second axis,

a connecting member including an arcuate part and a part provided with a threaded bore and including a threaded member adjustably engaging said threaded bore, said pivot on said one lever forming a stop for the arcuate member, a transverse projection on said threaded member partially rotatable in the arcuate recess in said other lever on a third axis crossing orthogonally the axis of the threaded bore, a knob on said threaded member to permit manual rotation of the threaded member to adjust the 0perative length of said connecting member, a hand-operabie lever having spaced pivots, one of which is pivotally secured to the pivot on said one lever and the other of which is pivotally secured to the arcuate part on a fourth axis which intersects the axis of the threaded bore, said hand-operable lever being adapted to shift the arcuate part between its stop-engaging position in which said fourth axis lies outside the pivot on said one lever and coplanar with said second and third axes, and a second position in which the jaws have been moved away from each other, the angular positions of the rectilinear levers for said two extreme positions of said hand-operable lever being determined by the operative length of the connccting member as adjusted by the knob and threaded memher, and a spring urging the rectilinear levers apart.

References Cited in the file of this patent UNITED STATES PATENTS 232,959 Hall et al. Oct. 5, 1880 639,812 Jensen Dec. 26, 1899 2,185,673 Luft Jan. 2, 1940 2,377,953 Matton June 12, 1945 2,523,385 Mead Sept. 26, 1950 2,538,149 Fanneneet et al. Jan. 16, 1951 2,543,922 Mead Mar. 6, 1951 

